title: Clinical and pathologic responses of American crows (Corvus brachyrhynchos) and fish crows (C ossifragus) to experimental West Nile virus infection.
abstract: West Nile virus (WNV)-associated disease has a range of clinical manifestations among avian taxa, the reasons for which are not known. Species susceptibility varies within the avian family Corvidae, with estimated mortality rates ranging from 50 to 100%. We examined and compared virologic, immunologic, pathologic, and clinical responses in 2 corvid species, the American crow (Corvus brachyrhynchos) and the fish crow (C ossifragus), following experimental WNV inoculation. Unlike fish crows, which remained clinically normal throughout the study, American crows succumbed to WNV infection subsequent to dehydration, electrolyte and pH imbalances, and delayed or depressed humoral immune responses concurrent with marked, widespread virus replication. Viral titers were approximately 3,000 times greater in blood and 30,000 to 50,000 times greater in other tissues (eg, pancreas and small intestine) in American crows versus fish crows. Histologic lesion patterns and antigen deposition supported the differing clinical outcomes, with greater severity and distribution of lesions and WNV antigen in American crows. Both crow species had multiorgan necrosis and inflammation, although lesions were more frequent, severe, and widespread in American crows, in which the most commonly affected tissues were small intestine, spleen, and liver. American crows also had inflammation of vessels and nerves in multiple tissues, including heart, kidney, and the gastrointestinal tract. WNV antigen was most commonly observed within monocytes, macrophages, and other cells of the reticuloendothelial system of affected tissues. Collectively, the data support that WNV-infected American crows experience uncontrolled systemic infection leading to multiorgan failure and rapid death.
authors.affiliation: Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado, USA. nmnemeth@uga.edu
authors.forename: N M
authors.initials: NM
authors.lastname: Nemeth
authors.forename: B V
authors.initials: BV
authors.lastname: Thomsen
authors.forename: T R
authors.initials: TR
authors.lastname: Spraker
authors.forename: J M
authors.initials: JM
authors.lastname: Benson
authors.forename: A M
authors.initials: AM
authors.lastname: Bosco-Lauth
authors.forename: P T
authors.initials: PT
authors.lastname: Oesterle
authors.forename: J M
authors.initials: JM
authors.lastname: Bright
authors.forename: J P
authors.initials: JP
authors.lastname: Muth
authors.forename: T W
authors.initials: TW
authors.lastname: Campbell
authors.forename: T L
authors.initials: TL
authors.lastname: Gidlewski
authors.forename: R A
authors.initials: RA
authors.lastname: Bowen
mesh_terms: D000818:Animals; D000835:Animals, Wild; D000914:Antibodies, Viral / Q000097:blood*; D000956:Antigens, Viral / Q000097:blood*; D001715:Bird Diseases / Q000401:mortality / Q000473:pathology* / Q000821:virology; D046368:Crows / Q000821:virology*; D004562:Electrocardiography / Q000662:veterinary; D005243:Feces / Q000821:virology; D013045:Species Specificity; D014766:Viremia / Q000662:veterinary; D014779:Virus Replication; D014901:West Nile Fever / Q000401:mortality / Q000473:pathology / Q000662:veterinary* / Q000821:virology; D014902:West Nile virus / Q000276:immunology* / Q000302:isolation & purification / Q000502:physiology
chemical_list: D000914:Antibodies, Viral; D000956:Antigens, Viral